public function callback_after_update($callback = null, $override_all = 0) { if (!$override_all) { $this->callback_after_update_ext[] = $callback; if ($this->callback_after_update == null) { $this->callback_after_update = array($this, 'extended_callback_after_update'); } } else { parent::callback_after_update($callback); } return $this; }